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Abstract:

The present invention provides compositions, methods, apparatus, and
systems to minimize environmental impact, water use, and overall cost of
drilling and hydraulic fracturing for crude oil and natural gas. Some
variations of the invention provide a fracturing-fluid additive
composition comprising a water-soluble portion of a biomass-pyrolysis
liquid. In some embodiments, the fracturing-fluid additive composition is
substantially biodegradable and is not toxic. Some variations provide
improved proppants for oil or gas well fracturing. Other variations of
this invention relate to drilling-fluid additive compositions, and
methods of using these compositions. This invention can significantly
improve the environmental, economic, and social sustainability associated
with drilling and fracturing for production of oil and gas.

Claims:

1. A fracturing-fluid additive composition comprising a water-soluble
portion of a biomass-pyrolysis liquid.

2. The composition of claim 1, wherein said composition comprises one or
more biomass-derived organic acids.

9. The composition of claim 1, wherein said composition is substantially
biodegradable.

10. A fracturing-fluid additive composition comprising one or more
biomass-derived compounds selected from the group consisting of organic
acids, aldehydes, ketones, furans, phenols, esters, alcohols, and
combinations thereof

11. The composition of claim 10, wherein said one or more biomass-derived
compounds are derived from a water-soluble portion of a biomass-pyrolysis
liquid.

12. The composition of claim 10, wherein said one or more biomass-derived
compounds are derived from a water-insoluble portion of a
biomass-pyrolysis liquid.

13. A fracturing fluid comprising water and an additive composition
containing a water-soluble portion of a biomass-pyrolysis liquid.

14. The fracturing fluid of claim 13, wherein said additive composition
comprises one or more biomass-derived compounds selected from the group
consisting of organic acids, aldehydes, ketones, furans, phenols, esters,
alcohols, and combinations thereof

15. The fracturing fluid of claim 13, said fracturing fluid further
comprising a proppant.

17. The fracturing fluid of claim 13, wherein said additive composition
is a breaker within said fracturing fluid.

18. The fracturing fluid of claim 13, wherein said additive composition
modifies the pH of said fracturing fluid.

19. The fracturing fluid of claim 13, wherein said additive composition
is effective to stimulate flow of oil or gas within an oil or gas well by
dissolving minerals, enlarging formation pores, initiating cracks,
etching channels, and/or increasing permeability in rock.

20. The fracturing fluid of claim 13, wherein said additive composition
is effective to stimulate flow of oil or gas within an oil or gas well by
cleaning the well borehole, casing, and/or formation, or by removing
filter cake buildup.

21. The fracturing fluid of claim 13, wherein said additive composition
includes one or more compounds that inhibit metal oxide precipitation.

22. The fracturing fluid of claim 13, wherein said additive composition
includes one or more compounds that inhibit the corrosion potential of
said fracturing fluid.

23. The fracturing fluid of claim 13, wherein said additive composition
includes one or more compounds that inhibit microbial growth within said
fracturing fluid or at a contact surface disposed adjacent to said
fracturing fluid.

24. The fracturing fluid of claim 13, wherein said additive composition
is renewable and biodegradable.

25. The fracturing fluid of claim 13, wherein said additive composition
reduces the chemical or physical potential for groundwater contamination
associated with said fracturing fluid.

Description:

[0001] PRIORITY DATA

[0002] This patent application claims priority under 35 U.S.C. §120
from U.S. Provisional Patent Application No. 61/491,188, filed May 28,
2011, the disclosure of which is hereby incorporated by reference herein
for all purposes.

FIELD OF THE INVENTION

[0003] The present invention generally relates to compositions, methods,
apparatus, and systems for drilling and hydraulic fracturing of wells.

BACKGROUND OF THE INVENTION

[0004] Oil and natural gas are common fossil-based resources used for the
production of transportation fuels, heat and power, materials, chemicals,
adhesives, pharmaceuticals, polymers, fibers and other products. Since
the first oil well drilled in 1859 and the introduction of the internal
combustion engine, the United States has been a major producer and
consumer of fossil resources (Drake Well Museum, 2012).

[0005] In 2010, the US produced over 2 billion barrels of oil and 26.8
trillion cubic feet of natural gas worth over $180 and $110 billion,
respectively. A significant amount of this production can be attributed
to advances in horizontal drilling and hydraulic fracturing. Previously
unrecoverable deposits have been freed up ensuring access to decades of
domestic natural gas and oil. In fact, without hydraulic fracturing, 17%
of oil and 45% of natural gas production would be lost within five years
(IHS Global Insight, 2009).

[0006] Oil and natural gas deposits are located all across the United
States and the World. It is estimated that the total amount of
technically recoverable natural gas resources worldwide is 22,600
trillion cubic feet of which shale gas is 6,622 trillion cubic feet or
nearly 30% (U.S. Department of Energy and Energy Information
Administration, 2011). Wells are drilled hundreds of meters deep in order
to gain access to the resources. Once drilled, new wells or old
unproductive wells are hydraulically fractured to stimulate production.

[0007] Drilling fluids or muds are used during the initial well bore to
cool the bit, lubricate the drill string, suspend and transport cuttings,
control hydrostatic pressure and maintain stability. Drilling fluids are
typically water- or oil-based but can be pneumatic. Water or oil is the
main ingredient in liquid drilling fluids. Barite, clay, polymers,
thinners, surfactants, inorganic chemicals, bridging materials, lost
circulation materials and specialized chemicals are also added to
engineer drilling fluid properties. Drilling fluids make up between 5-15%
of drilling costs (Ben Bloys, 1994).

[0008] Hydraulic fracturing was developed in the 1940's to increase
productivity of oil and gas wells. Hydraulic fracturing creates and
maintains cracks within oil and gas formations providing a clear path for
oil and gas to flow. Fracturing can be performed in vertical and
horizontal wells. During a fracturing operation, perforations are made
through cement casing into the oil and gas formation using explosive
charges. Fracturing fluids are injected into the well at high pressures
to create new cracks while further expanding and elongating the cracks
formed by the explosives (American Petroleum Institute, 2010).

[0009] Fracturing fluids are composed primarily of water (87-94%) and
proppant such as sand (4-9%). Sand mixed with the fracturing fluids is
used to prop open formation cracks and maintain a clear path for oil and
natural gas. The remaining fracturing fluid (0.5-3%) is composed of
chemicals that aid the fracturing process. Chemical additives are mixed
into the drilling fluid depending on the well and formation properties.
Chemicals are used to dissolve minerals, reduce friction, prevent
scaling, maintain fluid properties (viscosity, pH, etc.), eliminate
bacteria (biocide), suspend the sand, prevent precipitation of metal
oxides, prevent corrosion, stabilize fluid, formation and wellbore,
thicken fluid (gelling agent) and breakdown the gel (breaker) (American
Petroleum Institute, 2010).

[0010] Hydraulic fracturing fluid is made in a step-wise procedure and
carefully engineered to accomplish the fracking process. In its most
basic form, a gelling agent such as gaur gum is first added to water and
hydrated. Next a breaker (oxidant or enzyme) is added which will break
the gel bonds after being pumped into the well. A crosslinking agent such
as borate is then added to the solution which immediately forms a
viscous, gelled solution. The purpose of the gel is to suspend the
proppant while being pumped into the well where it is wedged into
formation fractures propping them apart.

[0011] Eventually the fracturing fluid must be removed from the well
leaving the proppant in the fractures to maintain open channels for oil
or gas to flow through. In order to pump the fracturing fluid out of the
well and leave the proppant behind the viscous gel must be broken down to
a viscosity less than 100 cP. Since the fracturing fluid is pumped into
the well in stages, precise amounts of breaker are mixed with the
fracturing fluid to break the entire gel solution simultaneously. Once
the entire gel is broken the fracturing fluid is pumped back to the
surface where it is stored in retention ponds or hauled away from the
well for treatment and disposal.

[0012] One of the challenges associated with drilling and hydraulic
fracturing is in using oil-based fluids. Oil-based fluids are subject to
environmental scrutiny and are costly since they may include substantial
quantities of refined petrochemicals or fuels, such as diesel fuel.

[0013] Another challenge associated with drilling and hydraulic fracturing
is reducing the amount of water used in the process. Depending on how
deep the well is, millions of gallons of water may be used during both
drilling and hydraulic fracturing (Ground Water Protection Council and
ALL Consulting, 2009). Recovered fluid is stored in open retention ponds
where it is left to settle and evaporate or trucked out to be treated. In
some cases, fluid is lost underground.

[0014] Another challenge associated with drilling and hydraulic fracturing
arises from the retention ponds themselves. Retention ponds contain the
recovered fluid, chemicals and cuttings from the well. Retention ponds
may be a source of ground water contamination if the containment area
gives way or the liner is pierced. Retention ponds also pose risks to
wildlife if exposed to chemicals. Furthermore, if wells are planned in
environmentally sensitive areas, retention ponds may not be permitted. In
this case cuttings and recovered fluids and chemicals must be transported
from site for treatment.

[0015] A criticism with drilling and hydraulic fracturing relates to the
types of chemicals used during the process and the hazards they may pose.
Though usually less than a couple percent of the entire fluid, common
chemical additives include hydrochloric acid, formic acid, citric acid,
boric acid, acetic acid, lauryl sulfate, polyacrylamide, ethylene glycol,
borate salts, potassium carbonate, potassium chloride, glutaraldehyde,
guar gum, isopropanol, petroleum distillates, sodium chloride, methanol
and 2-butoxyethanol.

[0016] Another criticism associated with drilling and hydraulic fracturing
is that groundwater contamination may occur in underground aquifers.
During drilling and hydraulic fracturing, cement and steel casing is
placed in the wellbore as a boundary between aquifers and the production
material. Nonetheless, many have complained about chemicals found in
drinking water and blame drilling and hydraulic fracturing. The
Environmental Protection Agency and other agencies are investigating if
and how drilling and hydraulic fracturing are linked with ground water
contamination (Environmental Protection Agency, 2009).

[0017] Another criticism associated with hydraulic fracturing is ground
water contaminated with natural gas. Landowners cite detectible amounts
of thermogenic methane in drinking water that contribute to poor health
of livestock and humans (Stephan G. Osborn, 2011).

[0018] In U.S. Pat. No. 5,067,566 (Nov. 26, 1991) a subterranean formation
fracturing method is disclosed where a hydratable polymer, crosslinking
agent and breaker are combined to form a fracturing fluid. A pH
regulating substance is added to the fluid which slowly hydrolyzes
forming an acid so that the breaker is activated and can control the
breaking point of the polymer gel. The patent notes that one of the
challenges with breakers is that they are difficult to control such that
the entire gel is broken simultaneously. Oxidant breakers are ineffective
at temperatures below 55° C. without added coreactants and,
although enzyme breakers can be used at lower temperatures, they are
sensitive to pH. The invention seeks to improve upon these breakers,
however it requires an additional pH regulating substance for enzymatic
breakers to be effective.

[0019] In U.S. Pat. No. 5,624,886 (Apr. 29, 1997) a subterranean formation
fracturing method is disclosed where a hydratable polymer, crosslinking
agent and breaker are combined to form a fracturing fluid. The breaker is
made of an insoluble oxidant and formed as a pellet. However, the
insoluble breaker is not evenly mixed with the fracturing fluid which may
prevent even breaking throughout the fluid. Furthermore, a solid,
insoluble, pelletized breaker is costly to manufacture and difficult to
incorporate into liquid fracturing fluids.

[0020] In U.S. Pat. No. 7,231,976 (Jun. 19, 2007) a method of treating a
well with a biodegradable fluid consisting of a lactic acid ester and a
fatty acid ester is disclosed. The biodegradable fluid may be emulsified
with alcohol and water using emulsifiers and used to remove pipe dope,
hydrocarbons and drilling muds. Furthermore, the biodegradable fluid may
act as a breaker catalyst to decrease the viscosity of fracturing fluids
or replace synthetic and oil based drilling muds. However, forming an
emulsion adds increased complexity and cost to a drilling and fracturing
operation.

[0021] In U.S. Pat. No. 5,678,632 (Oct. 21, 1997) a method of acidizing an
underground reservoir by injecting a substrate and enzyme which converts
the substrate into an organic acid is disclosed. However, it is noted
that the enzyme may be inactive under certain temperatures, pressures and
environments and fail to treat the reservoir.

[0022] In U.S. Pat. No. 5,639,715 (Jun. 17, 1997) an environmentally
non-toxic drilling fluid is disclosed. The drilling fluid is made in part
from a surfactant that imparts anti-bit balling, lubricity, salt
tolerance and non-toxic properties. However, the non-toxic surfactant is
only an additive to the drilling fluid which may include other toxic
compounds.

[0023] What are needed in the art are methods or products that minimize
environmental impact, scrutiny, water-use and costs of drilling, treating
and hydraulic fracturing for oil and gas. Furthermore, products that are
environmentally benign, have reduced toxicity and do not contaminate
drinking water are needed. A preferred fast pyrolysis process that
converts biomass into renewable bio-oil fractions and carbon-rich biochar
will reduce water use, hazardous chemicals and fluid cost while improving
the environmental sustainability of drilling, treating and hydraulic
fracturing for oil and gas.

SUMMARY OF THE INVENTION

[0024] The present invention addresses the aforementioned needs in the
art, as will now be summarized and then further described in detail
below.

[0025] Some variations of the invention provide a fracturing-fluid
additive composition comprising a water-soluble portion of a
biomass-pyrolysis liquid.

[0026] In some embodiments, the fracturing-fluid additive composition
comprises one or more biomass-derived organic acids. In some embodiments,
the fracturing-fluid additive composition comprises biomass-derived
organic acids include acetic acid. In some embodiments, the
fracturing-fluid additive composition comprises biomass-derived organic
acids include formic acid. In some embodiments, the fracturing-fluid
additive composition comprises one or more biomass-derived aldehydes or
ketones. In some embodiments, the fracturing-fluid additive composition
comprises one or more biomass-derived phenols. In some embodiments, the
fracturing-fluid additive composition comprises one or more
biomass-derived alcohols.

[0027] In some embodiments, the fracturing-fluid additive composition
comprises contains at least 50 wt % water and is substantially
biodegradable.

[0028] Some embodiments of the invention provide a fracturing-fluid
additive composition comprising one or more biomass-derived compounds
selected from the group consisting of organic acids, aldehydes, ketones,
furans, phenols, esters, alcohols, and combinations thereof. In certain
embodiments the fracturing fluid additive composition contains one or
more biomass-derived compounds are derived from a water-soluble portion
of a biomass-pyrolysis liquid. In certain embodiments the fracturing
fluid additive composition contains one or more biomass-derived compounds
are derived from a water-insoluble portion of a biomass-pyrolysis liquid.

[0029] Other variations of the present invention provide a fracturing
fluid comprising water and an additive composition containing a
water-soluble portion of a biomass-pyrolysis liquid.

[0030] In some variations of fracturing fluids, an additive composition
comprises one or more biomass-derived compounds selected from the group
consisting of organic acids, aldehydes, ketones, furans, phenols, esters,
alcohols, and combinations thereof.

[0031] In some embodiments, the fracturing fluid further comprises a
proppant. In other embodiments of fracturing fluids, a proppant comprises
biochar.

[0032] In some variations of fracturing fluids, an additive composition is
a breaker within said fracturing fluid. In other variations, an additive
composition modifies the pH of said fracturing fluid.

[0033] In some embodiments of fracturing fluids, an additive composition
is effective to stimulate flow of oil or gas within an oil or gas well by
dissolving minerals, enlarging formation pores, initiating cracks,
etching channels, and/or increasing permeability in rock. In other
embodiments of fracturing fluids, an additive composition is effective to
stimulate flow of oil or gas within an oil or gas well by cleaning the
well borehole, casing, and/or formation, or by removing filter cake
buildup.

[0034] Some variations of fracturing fluids include an additive
composition with one or more compounds that inhibit metal oxide
precipitation. In other variations of fracturing fluids, an additive
composition includes one or more compounds that inhibit the corrosion
potential of said fracturing fluid. In other variations of fracturing
fluids, an additive composition includes one or more compounds that
inhibit microbial growth within said fracturing fluid or at a contact
surface disposed adjacent to said fracturing fluid.

[0036] Some variations of the invention provide a fracturing-fluid
additive composition comprising the aqueous phase of a biomass-pyrolysis
liquid, or a water-soluble portion of a biomass-pyrolysis liquid.

[0037] In some embodiments, the fracturing-fluid additive composition
comprises one or more biomass-derived organic acids, such as acetic acid
or formic acid. In some embodiments, the fracturing-fluid additive
composition comprises one or more biomass-derived aldehydes or ketones.
In some embodiments, the fracturing-fluid additive composition comprises
one or more biomass-derived furans. In some embodiments, the
fracturing-fluid additive composition comprises one or more
biomass-derived phenols. In some embodiments, the fracturing-fluid
additive composition comprises one or more biomass-derived esters. In
some embodiments, the fracturing-fluid additive composition comprises one
or more biomass-derived alcohols. In some embodiments, the
fracturing-fluid additive composition comprises oxygenated decomposition
products derived from cellulosic biomass. The decomposition products may
include levoglucosan or organic acids, for example.

[0039] Some embodiments of the invention provide a fracturing-fluid
additive composition produced by a process comprising pyrolyzing biomass
into a pyrolysis oil and recovering an aqueous phase from the pyrolysis
oil, wherein the fracturing-fluid additive composition comprises the
aqueous phase. The pyrolysis oil may be obtained from biomass slow
pyrolysis or biomass fast pyrolysis. In certain embodiments, the
pyrolysis oil is obtained from one or more liquid fractions obtained from
biomass fast pyrolysis followed by condensing pyrolysis vapors and
electrostatically precipitating pyrolysis aerosols. In certain
embodiments, the fracturing-fluid additive composition comprises
condensed biomass-pyrolysis vapors, electrostatically precipitated
biomass-pyrolysis aerosols, and water.

[0040] Preferably, the fracturing-fluid additive composition is
substantially biodegradable. Preferably, the fracturing-fluid additive
composition is not toxic, and/or reduces the toxicity of the fracturing
fluid into which the additive is combined.

[0041] Other variations of the present invention provide fracturing fluids
that include water, a proppant, an additive composition as described, and
optionally other chemicals. In some embodiments, the proppant comprises
biochar.

[0042] In some embodiments of fracturing fluids, an additive composition
includes one or more acids that dissolve minerals, enlarge formation
pores, initiate cracks, etch channels and increases permeability in rock
to increase production or otherwise stimulate flow within an oil or gas
well.

[0043] In some embodiments of fracturing fluids, an additive composition
includes one or more acids that cleans the well borehole, casing and
formation and removes filter cake buildup to increase production or
otherwise stimulate flow within an oil or gas well.

[0044] In some embodiments of fracturing fluids, an additive composition
includes one or more acids that reduce metal oxide precipitation from the
fracturing fluid.

[0045] In some embodiments of fracturing fluids, an additive composition
includes one or more compounds that inhibit the corrosion potential of
the fracturing fluid.

[0046] In some embodiments of fracturing fluids, an additive composition
includes one or more aldehydes that inhibit microbial growth within the
fracturing fluid or at a surface of contact with the fracturing fluid.

[0047] In various embodiments of fracturing fluids, an additive
composition modifies the properties of the fracturing fluid. Such
properties may include, but are not limited to, pH, viscosity, density,
lubricity, or stability. The additive composition may increase or
decrease the viscosity of the fracturing fluid, or even be selected to
maintain viscosity of the fracturing fluid as temperatures increase.

[0048] In some embodiments of fracturing fluids, an additive composition
is a gelling agent, crosslinker, breaker, and/or clay stabilizer within
the fracturing fluid.

[0049] In some embodiments of fracturing fluids, an additive composition
prevents scale deposits from forming within a borehole, drill string,
drill bit, casing and pipe. In some embodiments, an additive composition
prevents corrosion within a borehole, drill string, drill bit, casing and
pipe.

[0050] In preferred embodiments of fracturing fluids, an additive
composition reduces water usage relative to the amount of water that
would have been used in the absence of the additive(s). In preferred
embodiments, an additive composition is renewable and biodegradable, and
reduces groundwater contamination.

[0051] Some variations of the invention provide improved proppants for oil
or gas well fracturing. In some embodiments, a proppant comprises
biochar. In certain embodiments, some portion, or all of, the proppant
consists essentially of biochar. The biochar, when packed into a
formation fracture channel, may allow hydrocarbons to diffuse through
pores of the biochar without plugging the fracture channel. The biochar
may include ash particles, which can also serve as proppants. In some
embodiments, at least a portion of the biochar additionally serves as a
matrix for one or more other compounds contained in the fracturing fluid.
In some embodiments, at least a portion of the biochar additionally
serves as a fluid loss control additive contained in the fracturing
fluid.

[0052] The present invention also relates to methods of using any of the
disclosed fracturing-fluid additive compositions, fracturing fluids, or
proppants. Any of these compositions or materials may be utilized to
hydraulically fracture a natural gas well, a crude-oil well, or an
oil-shale well, for example.

[0053] In some variations, the invention provides a method of sequestering
carbon, the method comprising obtaining or producing biochar from
biomass; utilizing the biochar as a fracturing proppant for an oil or gas
well; and leaving at least a portion of the biochar within the oil or gas
well to sequester carbon contained in the biochar.

[0054] Other variations of this invention relate to drilling fluids and
drilling-fluid additive compositions. In some embodiments, a
drilling-fluid additive composition comprises the water-soluble portion
of a biomass-pyrolysis liquid. In these or other embodiments, a
drilling-fluid additive composition comprises the water-insoluble portion
of a biomass-pyrolysis liquid.

[0055] In some embodiments, a drilling-fluid additive composition
comprises one or more biomass-derived organic acids, such as acetic acid
or formic acid. In some embodiments, a drilling-fluid additive
composition comprises one or more biomass-derived aldehydes, ketones
furans, or phenols. In some embodiments, a drilling-fluid additive
composition comprises lignin-decomposition products and/or oxygenated
decomposition products (e.g., levoglucosan) derived from cellulosic
biomass.

[0057] A drilling-fluid additive composition may contain any amount of
water, from no water to 90 wt % or more water. In some embodiments, the
composition contains at least 15 wt %, 30 wt %, 50 wt %, 70 wt %, or 90
wt % water.

[0058] In some embodiments, a drilling-fluid additive composition is
produced by a process comprising pyrolyzing biomass into a pyrolysis oil
and recovering an aqueous phase from the pyrolysis oil, wherein the
drilling-fluid additive composition comprises the aqueous phase. In some
embodiments, a drilling-fluid additive composition is produced by a
process comprising pyrolyzing biomass into a pyrolysis oil and recovering
a water-insoluble phase from the pyrolysis oil, wherein the
drilling-fluid additive composition comprises the water-insoluble phase.
The pyrolysis oil may be obtained from biomass slow pyrolysis or fast
pyrolysis, for example.

[0059] In some embodiments, a drilling-fluid additive composition is
produced by a process comprising pyrolyzing biomass into a pyrolysis oil
and recovering an aqueous phase and a water-insoluble phase from the
pyrolysis oil, wherein the drilling-fluid additive composition comprises
the aqueous phase and/or the water-insoluble phase. The drilling-fluid
additive composition may include the aqueous phase, the water-insoluble
phase, or both of these in any combination.

[0060] Preferably, a drilling-fluid additive composition is substantially
biodegradable and non-toxic, and/or reduces the toxicity of the drilling
fluid into which the additive is combined.

[0061] In some embodiments, a drilling-fluid additive composition improves
stability of a wellbore, creates a largely impermeable layer in a
wellbore, creates a flexible plug or sealant in a wellbore or casing,
and/or creates a flexible plug or sealant in a casing for cementing.

[0062] Variation of this invention also relate to drilling fluids that
include a bio-based additive composition as disclosed. The bio-based
additive composition may modify the pH, viscosity, density, or lubricity
of the drilling fluid. Additionally, the bio-based additive composition
may modify the rheology of the drilling fluid. In some embodiments, the
bio-based additive composition is shear-thinning and/or thixotropic.

[0063] In some embodiments, the bio-based additive composition acts as a
gelling agent within the drilling fluid. In some embodiments, the
bio-based additive composition acts as a surfactant within the drilling
fluid. The additive composition may also act as an emulsion breaker
within a drilling fluid, depending in the nature of the drilling fluid
and other conditions present.

[0064] In various embodiments, a drilling fluid with an additive
composition, as provided by the invention, further includes one or more
compounds selected from the group consisting of cellulose,
carboxymethylcellulose, starch, bentonite clay, barium sulfate, calcium
carbonate, hematite, xanthan gum, guar gum, and glycol.

[0065] In some embodiments, a drilling fluid comprises biochar. The
drilling fluid may further include ash. In some embodiments, a drilling
fluid comprising a bio-based asphalt.

[0066] Some embodiments also provide drilling lost-circulation materials
or drilling fluid scavenger materials, such as materials that contain
biochar. In some embodiments, a lost-circulation material or drilling
fluid scavenger material comprises a composition that is the same as one
of the compositions described above with reference to drilling-fluid
additive compositions.

[0067] Methods of using the drilling fluids or drilling-fluid additive
compositions are also provided. In some embodiments, a method of drilling
a wellbore comprises utilizing a drilling fluid as disclosed. The
wellbore may be drilled for exploration or extraction of crude oil or
natural gas, for example. In some embodiments, the drilling fluid, or a
bio-based portion thereof, is introduced in varying amounts to
dynamically respond to drilling performance.

[0068] Other variations of the invention relate to methods of using
biochar. In some embodiments, a method includes introducing biochar
directly or indirectly to an oil or gas reserve pit to stabilize or
thicken solids contained in the reserve pit; to reduce the reclamation or
remediation time associated with the reserve pit; to absorb suspended
solids contained in the reserve pit; to remove contaminants and/or toxic
materials in the reserve pit; and/or to sequester carbon contained in the
biochar. In some embodiments, a method includes introducing cement
containing porous biochar to an oil or gas well casing to reduce annular
pressure buildup, and/or to sequester carbon. The biochar is produced
from a biomass conversion process, such as (but not limited to) biomass
slow or fast pyrolysis.

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The advantages of the technology described may be better understood
by referring to the descriptions below with the accompanying drawings.
The drawings are not to scale and represent exemplary configurations that
depict general principles of the technology. Dotted lines within the
figures are representative of optional process streams.

[0071]FIG. 2 provides an exemplary oil or gas hydraulic fracturing
process coupled with a preferred fast pyrolysis process that converts
biomass into renewable bio-oil fractions to reduce chemical and water use
and modify hydraulic fracturing fluid properties and carbon-rich biochar
to use as a proppant, sequester carbon and improve the environmental
sustainability of hydraulic fracturing.

[0072]FIG. 3 provides an exemplary chemical composition of any one fast
pyrolysis oil fraction or the aqueous phase of whole bio-oil whose
properties enable it to be used as a drilling and/or fracturing fluid
additive.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0073] The compositions, apparatus, systems, and methods of the present
invention will now be described in detail by reference to various
non-limiting embodiments, including the figures which are exemplary only.

[0074] Unless otherwise indicated, all numbers expressing dimensions,
capacities, and so forth used in the specification and claims are to be
understood as being modified in all instances by the term "about."
Without limiting the application of the doctrine of equivalents to the
scope of the claims, each numerical parameter should at least be
construed in light of the number of reported significant digits and by
applying ordinary rounding techniques.

[0075] The present invention may be practiced by implementing method steps
in different orders than as specifically set forth herein. All references
to a "step" may include multiple steps (or substeps) within the meaning
of a step. Likewise, all references to "steps" in plural form may also be
construed as a single process step or various combinations of steps.

[0076] The present invention may be practiced by implementing process
units in different orders than as specifically set forth herein. All
references to a "unit" may include multiple units (or subunits) within
the meaning of a unit. Likewise, all references to "units" in plural form
may also be construed as a single process unit or various combinations of
units.

[0077] As used in this specification and the appended claims, the singular
forms "a," "an," and "the" include plural referents unless the context
clearly indicates otherwise.

[0078] Some compositions are described in this patent application as
"comprising" one or more particular species, while some compositions are
described as "consisting essentially of one or more particular species.
The transitional phrases "comprising," "consisting essentially of and
"consisting of define the scope of a claim with respect to what unrecited
additional components or steps, if any, are excluded from the scope of
the claim. The transitional term "comprising," which is synonymous with
"including" or "containing" is inclusive or open-ended and does not
exclude additional, unrecited elements or method steps. The transitional
phrase "consisting essentially of limits the scope of a claim to the
specified materials or steps and those that do not materially affect the
basic and novel characteristic(s) of the claimed invention.

[0079] The term "additive" should be broadly construed in this patent
application to mean any amount of a particular species or mixture of
species, from an amount that is just detectable according to known
analytical techniques, up to and including an amount that constitutes
essentially the entirety of a composition. Typically an additive will be
added to a core composition, such as water, but the term additive (or
"additive composition") does not preclude an additive being used as a
composition per se for a suitable application.

[0080] "Drilling," for the purpose of the present invention, is any method
to cut a borehole into the ground (whether onshore or offshore) at any
suitable depth. "Drilling fluid", "drilling mud," or "completion fluid,"
for the purpose of the present invention, is any fluid or material used
in a drilling process and put down into a borehole. "Cuttings," for the
purpose of the present invention, are any crushed rock (often shale)
pieces removed from the borehole with drilling fluid.

[0081] "Hydraulic fracturing fluid," "fracturing fluid," "fracking fluid"
"fracking mud," "treatment fluid," "slickwater," or "pad" for the purpose
of the present invention, is any fluid or material used in a hydraulic
fracturing process, a well stimulation, completion, treatment or any
other technique, and injected into borehole with the purpose of improving
the process, permeability of the formation and increasing production.
"Hydraulic fracturing," "fracking," "fracturing," or "hydrofracking" for
the purpose of the present invention, is any method whereby fluids are
injected into a borehole to create fissures in the formation and increase
well production and increase permeability of a formation. "Well
completion," "well stimulation," or "well treatment" for the purpose of
the present invention, may include "hydraulic fracturing," "acidizing,"
"open hole," "conventional perforated," "sand exclusion," "permanent,"
"multiple zone," and/or "drainhole," completion techniques. A "reserve
pit" as used herein is any structure or containment region for containing
one or more materials used during production of oil or gas, such as
during drilling or fracturing operations.

[0083] Some embodiments are particularly useful for formations that
contain primarily natural gas, but the present invention is by no means
limited to such embodiments. Any reference to "oil and gas," "oil or
gas," or "oil and/or gas" are meant to be used interchangeably to mean
that a particular formation may include, or be drilled or fractured to
produce, primarily gas, primarily oil, or any combination therebetween.
In addition, the principles of the invention may be utilized for
production (recovery) of primarily water from a geological structure.

[0084] "Biomass," for the purpose of the present invention, is any
material not derived from fossil resources and comprising at least
carbon, hydrogen, and oxygen. Biomass includes, for example, plant and
plant-derived material, vegetation, agricultural waste, forestry waste,
wood waste, and paper waste. "Bio-oil fractions" and "water-rich
fraction," for the purpose of the present invention, are liquid products
derived from biomass pyrolysis. In general the water-rich fraction may
contain between 50-90 wt % water. "Biochar," for the purpose of the
present invention, is a solid, carbon-rich, biomass derived product, such
as that produced from fast pyrolysis.

[0086] Bio-oil is a dark brown, liquid-form of biomass. Also known as
pyrolysis oil, biocrude oil, wood oil and pyroligneous acid, it contains
a mixture of up to 400 organic compounds. Conventional bio-oil has high
water and oxygen content, low energy content, high acidity and general
instability. These poor properties prevent it from integrating into
existing markets or blending with hydrocarbons without expensive
upgrading. Bio-oil, however, can be separated into aqueous or water
soluble and organic or water insoluble phases using separation techniques
(Tushar P. Vispute, 2009; Lucia Garcia, 2000). The aqueous phase will
contain more water than the organic phase. The "aqueous phase" is a
water-rich pyrolysis liquid that will typically contain at least 50 wt %
water while the "organic phase" will typically contain less than 10 wt %
water. For the purpose of this invention, aqueous phase bio-oil may be
functional in water-rich fraction applications and organic phase bio-oil
may be functional in other bio-oil fraction applications.

[0087] Non-condensable gases include hydrogen, carbon monoxide, carbon
dioxide, methane, and other light hydrocarbons. Non-condensable gases may
also include inert gases used in the pyrolysis reactor. Typically,
non-condensable gases represent about 10 wt % to about 25 wt % of
pyrolysis products.

[0088] Biochar or char is a solid product of biomass pyrolysis. Fast
pyrolysis seeks to maximize liquid bio-oil yield and minimize biochar
yield. Biomass with high lignin and ash content tend to increase biochar
yields while slow heating rates, long vapor residence times and high
pressures lead to additional char formation.

[0089] A particular advantage of the present invention is using bio-oil
fractions from a fast pyrolysis fractionation and biochar as renewable,
biodegradable additives or replacements for water and chemicals use in
drilling and hydraulic fracturing fluids. Bio-oil fractions may be
collected using simple, low-cost, fractionation technology downstream of
biomass fast pyrolysis. Bio-oil fractions have improved properties over
conventional bio-oil since much of the water and acidic compounds are
separated into a single fraction. Using bio-oil fractions and biochar is
a new and preferred approach for improving the environmental outlook of
drilling and hydraulic fracturing for two reasons. One, bio-oil fractions
can be used to reduce and/or replace water and chemical usage of drilling
and fracturing fluids, and two, bio-oil fractions minimize any
environmental implications since they are renewable, biodegradable and
have low toxicity.

[0090] In some variations, the present invention incorporates technology
described in U.S. Pat. No. 8,100,990 entitled "Methods for Integrated
Fast Pyrolysis Processing of Biomass" issued Jan. 24, 2012 to Ellens et
al., which is incorporated by reference herein in its entirety.

Drilling

[0091] With reference to exemplary FIG. 1, the method and equipment in
system 100 is used to drill a borehole to recover oil, natural gas, water
or any other fluid and subterranean material.

[0092] The purpose of unit 105, drilling platform and equipment (includes
the derrick) is to support, rotate and add pipe to the drilling string
(pipe joints) as the drilling bit cuts out rock from the borehole. As the
borehole is drilled, drilling fluid or drilling mud is pumped from unit
130 (drilling fluid tanks), through unit 145 (drilling fluid pumps) into
unit 105 down through the drilling string, out of the drilling bit, into
the hole and out the top of the borehole into unit 110, shale shakers.

[0093] Drilling fluids are composed of a base fluid that is usually water
or oil (e.g. diesel, mineral oil, or synthetic oils), weighing agents
such as barium sulfate (barite), clay, surfactants and other additives.
Drilling fluid is used to cool and turn the bit, lubricate the drill
string, suspend and transport cuttings, control hydrostatic pressure to
prevent formation fluids from entering the borehole, support the well and
formation walls to prevent collapse, stabilize exposed underground
surfaces, and add buoyancy to reduce stress on heavy drilling tools.

[0094] Drilling fluid, drilled solids and cuttings leave unit 105 and
enter unit 110, shale shakers to remove coarse cuttings. Unit 110, shale
shakers, is one of the most important pieces of equipment on the entire
rig. Modern rigs may have 4 or more shale shakers. The shakers are fitted
with a series of vibrating screens to separate material based on
size--liquid phase and fine solids pass through the screens while larger
material does not.

[0095] After cuttings are separated from drilling fluid in unit 110 they
are collected and transported to unit 115, reserve pits for dry land
rigs. Offshore rigs do not have reserve pits and discard cuttings onto
the bottom of the lake or ocean. In the case of dry land drilling,
reserve ponds are also called earthen pits; these pits are used to
dispose of drilling cuttings, solids, mud, fluids and chemicals. The pit
size may range from 0.3 -0.6 acres depending on the well depth. Solids
settle to the bottom, while fluids on top are available for re-use in
emergencies. Reserve pits are fitted with a synthetic liner. In some
embodiments, reserve pits are left to evaporate and dry out, leaving the
liner to encapsulate and bury remaining solids. In another embodiment,
benign solids may be buried without the liner, or contaminated solids may
need to be transported away from the pit for alternate disposal. Closed
loop drilling systems and alternative drilling waste disposal systems
that don't require reserve pits are available, but less common. Reserve
pits are an environmental concern because of their potential for
contamination and wildlife harm. If not carefully controlled and managed,
reserve pits can contaminate soil, groundwater and surface water (Ramirez
Jr., 2009). In a preferred embodiment, biochar from unit 150, fast
pyrolysis process, is used in unit 115 as a reserve pit remediation and
carbon sequestration agent.

[0096] Recycled drilling fluid from unit 110, shale shakers, is subjected
to further separation and cleaning in a combination of equipment in unit
120, degasser, desander and desilter. The purpose of unit 120 is to
remove cutting and drilling solid materials from the drilling fluid
because they are abrasive and difficult to pump. The first step in unit
120 is a degasser that uses vacuum pressure or gravity to separate
entrained gases (e.g. air, H2S, methane, etc.) from the fluids. The
gas may be flared. The second step in unit 120 is a desander and desilter
used to remove sand and silt from the drilling fluids. These devices are
functionally identical to a gas cyclone but are called hydrocyclones
since they separate solids from liquids using centrifugal forces.
Desanders are typically larger and remove larger size particles than
desilters. Separated sand, silt and other drilling solids are collected
and transported to unit 115, reserve pit.

[0097] Drilling fluid from unit 120 is transported to unit 125, solids
control. Here, additional cleaning steps may be included after the
desilter, usually to control the fine solids content of the drilling
fluid. Unit 125 uses a screen separation step to recover, conserve or
recycle weighting agents added to the drilling fluid. Common weighting
agents are dense materials such as barite or barium sulfate. Recovered
solids are recycled and reused or transported to the reserve pit, unit
115.

[0098] Drilling fluids from unit 125 are transported to unit 130, drilling
fluid tanks or mud tanks The purpose of unit 130 is to mix and prepare
drilling fluid for service in one or more tanks or pits before being
pumped into the borehole. In one embodiment, drilling fluid is recycled
from the borehole and cleaned in units 110, 120 and 125 before entering
unit 130 and then is recycled back to the borehole.

[0099] In another embodiment, before the borehole is drilled, drilling
fluid is prepared in unit 130. Additives and chemicals from unit 135 are
mixed with base drilling fluids from unit 140. Additives that may be used
usually fall into the following categories: (1) weight materials, (2)
viscosifiers, (3) scavengers, (4) shale stabilizers, (5) well protection,
(6) defoamers, (7) lubricants, and (8) dispersants and deflocculants.
Additives can be solid or liquid, and may have separate storage and/or
receiving tanks or vessels in unit 135. In some embodiments unit 135 is
capable of mixing dry and/or liquid additives and may be fully integrated
with unit 130 and/or unit 140.

[0100] The purpose of unit 140 is to store base drilling fluids in storage
tanks Drilling fluid is usually water-based (fresh or brine water), or
oil-based (e.g., diesel, mineral oil, or synthetic oil). For dry land
drilling, storage tanks may be mobile tanker trucks or stationary tanks
For ocean or fresh water drilling there is no need to store drilling
fluids since the surrounding water is used. Base drilling fluids are
transported to unit 135 for mixing with additives or to unit 130 for
mixing and storage.

[0101] Clean and recycled drilling fluid from unit 130 is suctioned out of
drilling fluid tanks into unit 145 where it is pumped by large
reciprocating pumps into unit 105 down the borehole. Drilling fluid pumps
in unit 145 are often called mud pumps. The high pressure pumps can
inject drilling fluid over 50 MPa (7,500 psi) into the well. From the
pumps, drilling fluid is discharged into a vertical, rigid standpipe
before entering the rotary hose (or kelly hose). The rotary hose is a
high pressure, flexible line that connects the standpipe to the remaining
components for injection of drilling fluid into the well. The flexible
rotary hose is important to allow for linear up and down motion of the
drillstring during operation.

[0102] Unit 150, biomass fast pyrolysis process, may be integrated with
the drilling rig to utilize excess heat and/or electrical power, or it
may be independent. In a preferred embodiment, biochar from unit 150 is
transported to unit 115, reserve pit for carbon storage, remediation,
stabilizer, and/or unit 130, drilling fluid tank and mixing hopper as a
weighting agent, viscosifier, or oxygen scavenger. In another preferred
embodiment, bio-oil fractions from unit 150 are transported directly into
unit 130, drilling fluid tank or into unit 135, mixing hopper as a
weighting agent, viscosifier, scavenger, surfactant, stabilizer,
lubricant, or other additive.

[0103] Bio-oil fractions can improve upon prior art when used in
conjunction with drilling fluids since fractions may replace or reduce
the use of chemical additives. In various embodiments, bio-oil fractions
do not require powder/liquid mixing, thereby increasing operator safety,
reducing cost, and/or reducing risk of exposure. In some embodiments,
bio-oil fractions are biodegradable, water-based fluids that decrease
concern over reserve pit location (e.g., proximity to wetlands or
streams), pose much lower risk for contaminating ground water, may cost
less than current additives, may reduce amount of water required, and may
be used to adjust and meet drilling fluid specifications (e.g. pH,
viscosity, density, etc.).

[0104] Once the borehole is completely drilled to a target depth, the well
in unit 105 is cased with steel alloy pipe. The pipe prevents the well
from collapsing. After each casing, drilling resumes to the next target
depth unit completed. Typically four strings of casing are inserted into
the well at different depths and diameters. From shortest and widest
casing to longest and most narrow, the casing strings are called
conductor, surface, intermediate and production casing (American
Petroleum Institute, 2009).

[0105] After each casing interval the casing is cemented in place to
secure the steel casing. Cement fills the annulus between the well wall
and casing itself. Before the cement is pumped down the casing, a plug is
inserted to prevent contamination and separate the cement from the
drilling fluid that remains in the borehole. Cement is then pumped down
into the casing until the specified volume is reached while drilling
fluids are displaced up and around the casing in the annulus. A second
plug is put down the casing following the cement. Drilling fluid is then
pumped into the casing on top of the second plug. When the first plug
reaches the bottom, pumping pressure is increased to rupture the plug so
that the cement turns around casing and is displaced up the annulus until
the top plug reaches the bottom. After the casing is cemented the
borehole is left alone so that the cement cures. This process is repeated
until the final production casing is in place. In one embodiment, biochar
is mixed in with the cement used for casing. Porous biochar may reduce
annular pressure buildup by collapsing and creating space for cement to
expand into as it hardens. In one embodiment, biochar serves to protect
the casing from deformation by reducing annular pressure buildup while
simultaneously sequestering carbon.

[0106] After the production casing is cemented and cured the well is ready
for well completion. This is the process that prepares the well for
production. Different types of well completion exist including open hole,
conventional perforated, sand exclusion, stimulation, acidizing,
permanent, multiple zone and drainhole completion, inter alia. The
completion type is selected depending on the targeted hydrocarbon
formation. In some embodiments solids-free completion fluids are used
during well completion to set screens, liners, packers, downhole valves
or shooting perforations in the production zone. Completion fluids are
designed so that the formation is not damaged. Often completion fluids
are brines such as chlorides, bromides and formates. Drilling fluids are
not often used for well completion due to their solids content, pH and
other properties. In one embodiment one or more bio-oil fractions are
used as additives, partial replacements and/or full replacements of well
completion fluids.

[0107]FIG. 3 illustrates a table of exemplary chemical groups and
corresponding weight percentage range found in bio-oil fractions and in
the aqueous phase of whole bio-oil. Bio-oil fractions from unit 150
and/or the aqueous phase of whole bio-oil can be used as drilling fluid
additives as demonstrated in FIG. 1. Bio-oil fractions contain between
0-90 wt % water. In one embodiment, bio-oil fractions containing between
56-90 wt % water are used as drilling fluid additives. Bio-oil fractions
contain between 0-30 wt % levoglucosan. In a preferred embodiment bio-oil
fractions containing between 0-5 wt % levoglucosan are used as drilling
fluid additives. Bio-oil fractions also contain between 0-25 wt %
carboxylic acids including acetic and formic acids. In a preferred
embodiment, bio-oil fractions containing between 10-25 wt % carboxylic
acids are used as drilling fluid additives. Bio-oil fractions also
contain furans in the range of 0-18 wt %; phenolics in the range of 0-24
wt %; guaiacols in the range of 0-15 wt %; syringols in the range of 0-18
wt % and other light organics in the range of 0-50 wt %. In a preferred
embodiment bio-oil fractions containing furans between 0-5 wt %;
phenolics between 0-5 wt %; guaiacols between 0-3 wt %; syringols between
0-5 wt %; and other light organics in the range of 5-30 wt % are used as
drilling fluid additives or replacements.

Hydraulic Fracturing

[0108] Hydraulic fracturing is a formation stimulation method used to
create additional permeability in a producing formation to allow
hydrocarbon fluids (oil and/or gas) or water to flow more easily toward
the wellbore for purposes of production. Hydraulic fracturing can be used
to overcome natural barriers to the flow of fluids to the wellbore.
Barriers may include naturally, low, permeability common in shale
formations or reduced permeability resulting from near-wellbore damage
during drilling activities.

[0109] With reference to exemplary FIG. 2, the method and equipment in
system 200 is used to hydraulically fracture a formation to create
additional production of oil, natural gas, water or any other fluid and
subterranean material. Hydraulic fracturing may be performed within any
well or formation, whether onshore or offshore, at any depth.

[0110] Typically hydraulic fracturing is performed on new wells or wells
with poor production. Hydraulic fracturing can be done in vertical wells
but also in horizontally drilled wells. Hydraulic fracturing takes place
after the casing is cemented in place and may be a part of the completion
phase.

[0111] Hydraulic fracturing involves perforating the well in the
production formation. In some embodiments, fracturing is accomplished by
pumping in liquids at high pressure. A hydraulic fracture may be formed
by pumping a fracturing fluid into the wellbore at a rate sufficient to
increase the pressure downhole to a value in excess of a critical
fracture pressure associated with the formation rock. The pressure causes
the formation to crack, allowing the fracturing fluid to enter and extend
the crack farther into the formation. To keep this fracture open after
the injection stops, a solid proppant is added to the fracture fluid, as
explained further below, and as shown in FIG. 2. The propped hydraulic
fracture then becomes a high-permeability conduit through which the
formation fluids can flow to the well.

[0112] In these or other embodiments, a series of explosive charges are
lowered into a well. Charges are triggered at the top of the well causing
an explosion that cuts through the casing, cement and fractures the
surrounding formation. The perforation process is repeated along the
length of the production formation. After the desired perforations have
been created, a hydraulic fracturing fluid is mixed and injected into the
well as indicated in FIG. 2.

[0113] Following fracturing by high pressures and/or explosions, the
fractured formation allows more hydrocarbons (e.g., methane, condensate,
ethane, oil) and/or water to be extracted since the formation walls are
more porous.

[0114] The purpose of unit 205, water storage is to hold water used as a
base for the fracturing fluid. Water is pumped into unit 220, blending
station where other chemicals, additives and proppant are added. Water
typically composes around 90% of the hydraulic fracturing fluid and may
require millions of gallons per well. Water for the drilling fluid is
typically brought on to site in tanker trucks which is costly.

[0115] The purpose of unit 210 is to store proppant for mixing into the
fracturing fluid in unit 220. Conventionally, proppant is hard silica
sand that usually makes up around 9% of the fracturing fluid mixture.
Proppant is injected into the well to prop fine cracks, fractures and
fissures open in the formation to create a path for hydrocarbons to
escape. In one embodiment, biochar from unit 245 is mixed with
conventional proppant (e.g., sand) and stored in unit 210.

[0116] Biochar particles can also prop, or assist in propping, fine
cracks, fractures, and fissures in the formation. In some embodiments,
the biochar includes a substantial concentration of ash, such as about 1
wt %, 5 wt %, 10 wt %, 20 wt % or more. The ash will vary in composition,
depending on what feedstock was used to produce the biochar, but
typically the ash will contain a significant fraction of silica. This
silica will be able to serve as a proppant in a similar manner as the
silica or sand particles in conventional proppant. Biochar, when packed
into the formation fracture may still allow hydrocarbons to pass through
due to its high porosity thereby improving upon prior art in which solid
proppants may plug the fracture channel. Additionally, in some
embodiments, introducing biochar into the well can effectively sequester
carbon when some portion (or all) of the biochar is not recovered from
the produced well.

[0117] The purpose of unit 215 is to store and meter chemicals and
additives into unit 220 where they are mixed with water from unit 205 and
proppant from unit 210. Many chemicals are used for hydraulic fracturing
to improve the process. Chemicals typically make up about 1% of the
hydraulic fracturing fluid. Common chemicals, their purpose and function
in the fracturing fluid are included in Table 1 (Ground Water Protection
Council and Interstate Oil and Gas Compact Commission, 2011). In one
embodiment bio-oil fractions are stored in unit 215.

[0119] Chemical additives and amounts are selected according to the
geographic location of the well, type of formation, and target production
fluid. Once the appropriate chemicals in unit 215 have been selected they
are mixed with proppant and water in unit 220, blending station. In one
embodiment bio-oil liquids are added to unit 220 from unit 245, fast
pyrolysis process. In a preferred embodiment a particular bio-oil liquid
composed largely of acids and water is added to unit 220 from unit 245,
fast pyrolysis process.

[0120] In preferred embodiments, fracturing-fluid additive compositions
comprise a water-soluble portion of a biomass-pyrolysis liquid. In these
or other embodiments, fracturing-fluid additive compositions comprise a
water-insoluble portion of a biomass-pyrolysis liquid. It will also be
recognized that even when it is desired to include primarily a
water-soluble portion of a biomass-pyrolysis liquid, some amount of
normally water-insoluble materials may be included in the
fracturing-fluid additive composition, such as by non-equilibrium
entrainment or other factors associated with particular preparation
techniques.

[0121] Bio-oil fractions can improve upon prior art when used in
conjunction with fracturing fluids. Bio-oil fractions can have the
following benefits: [0122] organic acids may be used to prevent
precipitation of metal oxides (iron control) [0123] acids used to
dissolve minerals and initiate cracks in rock [0124] acids also used to
adjust pH of fluid to maintain effectiveness of other components [0125]
fractions can reduce water usage [0126] fractions can be used as a
breaker for the gel [0127] fractions can be used to prevent corrosion and
biological activity [0128] fractions can adjust fracturing fluid
properties (e.g., viscosity, lubricity, stability, density) [0129]
fractions can maintain fracturing fluid properties under changing
temperature and pressure [0130] using bio-derived material to accomplish
the same purpose as fossil based chemicals [0131] reduced environmental
threat and public scrutiny [0132] renewable and biodegradable materials
minimize environmental impact

[0133] In another preferred embodiment biochar from unit 245 is blended
into unit 220. Biochar is a solid, carbon-rich material that may be used
as a proppant and simultaneously sequester carbon when pumped below
ground.

[0134] Hydraulic fracturing fluid from unit 220, blending station is
pumped as a low pressure slurry to unit 225, pumping station. The purpose
of unit 225 is to inject the fracturing fluid into the borehole in unit
230, wellhead. High volume pumps are used to quickly inject fracturing
fluid at high pressure into the formation. The pumps are capable of
creating pressures up to 100 MPa (15,000 psi) and flowrates over 265 L/s
(100 barrels/minute).

[0135] The high-pressure hydraulic fracturing fluid slurry enters unit
230, wellhead, from unit 225. As the fracturing fluid is injected into
the well it penetrates the casing perforations into the production
formation. The high pressure creates new fractures in the rock while
widening and elongating existing ones. The fracturing fluid also serves
to dissolve minerals, enlarge formation pores, initiate cracks, etch
channels and increases permeability in rock to increase production or
otherwise stimulate flow within an oil or gas well.

[0136] Proppant suspended in the fracturing fluid by gelling agents such
as gaur gum and polysaccharides is carried deep into the formation and
props the cracks open. Without the proppant, fractures would seal up
after releasing the pressure.

[0137] Biochar may also serve as a fluid loss control additive by blocking
formation cracks to prevent hydraulic fracturing fluid from seeping out
of the wellbore before the formation.

[0138] Recovered and produced fluids and fine solids are swept out of the
well by the fracturing fluid and transported to unit 235, reserve pits.
Reserve pits are lined with a synthetic liner to prevent leaking and
ground water contamination. Reserve pits store recovered hydraulic
fracturing fluids, other produced fluids, loose proppant and chemical
additives. In some embodiments fluids and chemicals are recycled and
reused at new hydraulic fracturing sites. In another embodiment, the
fluids evaporate and the solids are wrapped in the liner and buried.

[0139] In preferred embodiments, biochar from unit 245 is transported to
the reserve pits to sequester carbon. Introduction of biochar directly or
indirectly into a reserve pit can have several other advantages. For
example, biochar may stabilize or thicken solids contained in the reserve
pit, reduce the reclamation or remediation time associated with the
reserve pit, capture toxic chemicals, and absorb suspended solids.

[0140] After the hydraulic fracturing fluid and produced fluids have been
recovered in unit 235 a production well head is placed on top of the well
in unit 230. At this time, hydrocarbons (typically oil or natural gas)
are extracted and stored in unit 240 before shipment through pipeline,
tanker truck, railroad, tanker ship, or another means of transport.

[0141]FIG. 3 illustrates a table of exemplary chemical groups and
corresponding weight percentage range found in bio-oil fractions and the
aqueous phase of whole bio-oil. Bio-oil fractions from unit 245 and/or
the aqueous phase of whole bio-oil can be used as hydraulic fracturing
fluid additives, in some embodiments, as demonstrated in FIG. 2. Bio-oil
fractions contain between 0-90 wt % water. In one embodiment, bio-oil
fractions containing between 56-90 wt % water are used as hydraulic
fracturing fluid additives. Bio-oil fractions contain between 0-30 wt %
levoglucosan. In a preferred embodiment bio-oil fractions containing
between 0-5 wt % levoglucosan are used as hydraulic fracturing fluid
additives. Bio-oil fractions also contain between 0-25 wt % carboxylic
acids including acetic and formic acids. In a preferred embodiment,
bio-oil fractions containing between 10-25 wt % carboxylic acids are used
as hydraulic fracturing fluid additives. Bio-oil fractions also contain
furans in the range of 0-18 wt %; phenolics in the range of 0-24 wt %;
guaiacols in the range of 0-15 wt %; syringols in the range of 0-18 wt %
and other light organics in the range of 0-50 wt %. In a preferred
embodiment bio-oil fractions containing furans between 0-5 wt %;
phenolics between 0-5 wt %; guaiacols between 0-3 wt %; syringols between
0-5 wt %; and other light organics in the range of 5-30 wt % are used as
hydraulic fracturing fluid additives or replacements.

[0142] In a preferred approach unit 245, fast pyrolysis process supplies
bio-oil fractions and biochar for a hydraulic fracturing process. As
mentioned, bio-oil fractions and biochar may be added to the fracturing
fluid to reduce environmental scrutiny by using renewable and
biodegradable products in place of toxic chemicals and to reduce water
use while maintaining fluid design specifications and quality.

Fast Pyrolysis and Bio-oil Fractionation Process

[0143] In a preferred approach, units 150 and 245 are described in U.S.
Pat. No. 8,100,990 entitled "Methods for Integrated Fast Pyrolysis
Processing of Biomass" issued Jan. 24, 2012 to Ellens et al., which is
incorporated by reference herein in its entirety.

[0144] Units 150 and 245 provide a method for pretreating and converting
biomass into liquid bio-oil fractions, solid biochar, and non-condensable
gas. These products are collected, processed, produced and recycled or
stored on site. The operation of units 150 and 245 are integral to the
production of value-added products including renewable bio-oil fractions
and biochar which can improve the environmental sustainability of
drilling and hydraulic fracturing.

[0145] In another approach, units 150 and 245 are biomass fast pyrolysis
processing facilities producing whole bio-oil, biochar and
non-condensable gas. In this embodiment, whole bio-oil is separated into
its organic and aqueous phases to provide bio-oil fractions and a
water-rich fraction, respectively.

[0146] In another approach, units 150 and 245 are any biomass processing
facility that may produce a biomass-derived liquid that is effective in
oil and gas drilling and/or fracturing processes. Preferably, units 150
and 245 are a biomass pyrolysis facility producing one or more
biomass-derived liquid fractions.

[0147] In one approach, the fast pyrolysis process, units 150 and 245, are
co-located with a well site so as to provide mutual benefit to one
another and add another level of integration. Co-location of a fast
pyrolysis processing plant with an well site may provide access to
utilities and auxiliary infrastructure. In another approach, unit 150 and
245 are independently owned and operated facilities that produce and sell
bio-oil fractions and biochar products to drilling, hydraulic fracturing
and fluid manufacturing and supply companies. The integrated fast
pyrolysis process in units 150 and 245 are able to use many different
feedstocks including lignocellulosic biomass and other carbon-based
energy sources. In certain approaches, the fast pyrolysis process uses
locally sourced biomass to produce bio-oil fractions as additives and/or
replacements for drilling and hydraulic fracturing fluids as well as
biochar for proppants, cementing additives and reserve pit remediation.

[0148] Bio-oil fractions, biochar, and the water-rich fraction when used
in the manner described can effectively minimize environmental impact,
scrutiny, water-use and costs of drilling, treating and hydraulic
fracturing for oil and gas. Furthermore, these products are
environmentally benign, have reduced toxicity and do not contaminate
drinking water. Fast pyrolysis can convert biomass into renewable bio-oil
fractions and carbon-rich biochar to reduce water use, hazardous
chemicals and fluid cost while improving the environmental sustainability
of drilling, treating and hydraulic fracturing for oil and gas.

EXAMPLES

[0149] The Examples set forth below are for illustrative purposes only and
are not intended to limit, in any way, the scope of the present
invention.

Example 1

Aqueous Phase of Bio-Oil Tested as a Breaker at 90° C.

[0150] Fracturing fluid samples treated with an aqueous phase pyrolysis
liquid (water-rich fraction) breaker were prepared in a blender and
analyzed to determine break time. A gelling agent containing a solution
of 54 wt % guar gum powder and 46 wt % vegetable oil was hydrated in 0.5
liters of de-ionized water for 2 minutes. Each sample was treated with a
quantity of aqueous phase pyrolysis liquid breaker diluted with
de-ionized water (100:1) and 14 wt % sodium tetraborate/methanol solution
to crosslink the gel. The aqueous phase pyrolysis liquid was produced
from oak biomass using a pilot scale fast pyrolysis system described in
U.S. Pat. No. 8,100,990. Sand, sieved between 20 and 30 mesh, was added
to each sample after crosslinking to visually determine the time required
to break the gel. A Brookfield DV-E rotational viscometer was used to
confirm a visually broken gel by ensuring a viscosity below 50 cP at
90° C.

[0151] The aqueous phase pyrolysis liquid concentration is shown as
gallons of 100:1 diluted pyrolysis liquid per 1000 gallons of de-ionized
water. Samples were sealed in high density polyethylene Nalgene bottles
and placed in a hot oil bath at 90° C. test temperature. Break
time is shown in Table 2 as visually determined. The results indicate
that break time is a function of aqueous phase pyrolysis liquid
concentration which provides a high degree of control.

[0152] Fracturing fluid samples treated with an aqueous phase pyrolysis
liquid (water-rich fraction) breaker were prepared in a blender and
analyzed to determine break time. A gelling agent containing a solution
of 53 wt % guar gum powder and 47 wt % vegetable oil was hydrated in 0.5
liters of de-ionized water for 2 minutes. Each sample was treated with a
quantity of aqueous phase pyrolysis liquid breaker diluted with
de-ionized water (100:1) and 13 wt % sodium tetraborate/methanol solution
to crosslink the gel. The aqueous phase pyrolysis liquid was produced
from oak biomass using a pilot scale fast pyrolysis system described in
U.S. Pat. No. 8,100,990. Sand, sieved between 20 and 30 mesh, was added
to each sample after crosslinking to visually determine the time required
to break the gel. A Brookfield DV-E rotational viscometer was used to
confirm a visually broken gel by ensuring a viscosity below 50 cP at
80° C.

[0153] The aqueous phase pyrolysis liquid concentration is shown as
gallons of 100:1 diluted pyrolysis liquid per 1000 gallons of de-ionized
water. Samples were sealed in high density polyethylene Nalgene bottles
and placed in a hot oil bath at 80° C. test temperature. Break
time is shown in Table 3 as visually determined. The results indicate
that break time is a function of aqueous phase pyrolysis liquid
concentration which provides a high degree of control.

[0154] Fracturing fluid samples treated with model compounds found in
aqueous phase pyrolysis liquid were prepared in a blender and analyzed to
determine break time. Acetic acid and methanol were found in a particular
aqueous phase pyrolysis liquid at about 12 wt % and 1.6 wt %,
respectively. Therefore, acetic acid and methanol were tested as model
compound breakers once diluted with de-ionized water to concentrations
similar to that found in diluted aqueous phase pyrolysis liquid. A
gelling agent containing a solution of 53 wt % guar gum powder and 47 wt
% vegetable oil was hydrated in 0.5 liters of de-ionized water for 2
minutes. Each was treated with a quantity and compound type analogous to
diluted pyrolysis liquid, as shown in Table 4 and 13 wt % sodium
tetraborate/methanol solution to cross link the gel. Sand, sieved between
20 and 30 mesh, was added to each sample after crosslinking to visually
determine the time required to break the gel. A Brookfield DV-E
rotational viscometer was used to confirm a visually broken gel by
ensuring a viscosity below 50 cP at 80° C.

[0155] The concentration of the model compounds is shown as gallons of
100:1 diluted acetic acid or methanol per 1000 gallons of de-ionized
water. Samples were sealed in high density polyethylene Nalgene bottles
and placed in a hot oil bath at 80° C. test temperature. Break
time is shown in Table 4 as visually determined. The experiment indicates
that model compounds were not effective compared to aqueous phase
pyrolysis oil. The results in Table 4 demonstrate that acetic acid and
methanol model compounds in and of themselves cannot be used as breakers
in hydraulic fracturing fluid since there was no evidence that the gel
was broken or that the compound concentration actually affects the break
time.

Aqueous Phase of Bio-Oil Tested as a Breaker at 80° C. Using a
Saline Solution

[0156] Fracturing fluid samples treated with an aqueous phase pyrolysis
liquid (water-rich fraction) breaker were prepared in a blender and
analyzed to determine break time. A gelling agent containing a solution
of 53 wt % guar gum powder and 47 wt % vegetable oil was hydrated in 0.5
liters of 1 molar saline solution for 2 minutes. Each sample was treated
with a quantity of aqueous phase pyrolysis liquid breaker diluted with
de-ionized water (100:1) and 13 wt % sodium tetraborate/methanol solution
to crosslink the gel. The aqueous phase pyrolysis liquid was produced
from oak biomass using a pilot scale fast pyrolysis system described in
U.S. Pat. No. 8,100,990. Sand, sieved between 20 and 30 mesh, was added
to each sample after crosslinking to visually determine the time required
to break the gel. A Brookfield DV-E rotational viscometer was used to
confirm a visually broken gel by ensuring a viscosity below 50 cP at
80° C.

[0157] The aqueous phase pyrolysis liquid concentration is shown as
gallons of 100:1 diluted pyrolysis liquid per 1000 gallons of 1 molar
saline solution. Samples were sealed in high density polyethylene Nalgene
bottles and placed in a hot oil bath at 80° C. test temperature.
Break time is shown in Table 5 as visually determined. The results
indicate that break time is a function of aqueous phase pyrolysis liquid
concentration which provides a high degree of control.

[0158] Aqueous Phase of Bio-Oil Tested as a Breaker at 80° C. Using
Buffered Solutions

[0159] Fracturing fluid samples treated with an aqueous phase pyrolysis
liquid (water-rich fraction) breaker were prepared in a blender and
analyzed to determine break time. A gelling agent containing a solution
of 53 wt % guar gum powder and 47 wt % vegetable oil was hydrated in 0.5
liters of de-ionized water for 2 minutes. Each sample was treated with a
quantity of aqueous phase pyrolysis liquid breaker diluted with
de-ionized water (100:1), pH 9.0 buffer solution and 13 wt % sodium
tetraborate/methanol solution to crosslink the gel. The aqueous phase
pyrolysis liquid was produced from oak biomass using a pilot scale fast
pyrolysis system described in U.S. Pat. No. 8,100,990. Sand, sieved
between 20 and 30 mesh, was added to each sample after crosslinking to
visually determine the time required to break the gel. A Brookfield DV-E
rotational viscometer was used to confirm a visually broken gel by
ensuring a viscosity below 50 cP at 80° C.

[0160] The aqueous phase pyrolysis liquid concentration is shown as
gallons of 100:1 diluted pyrolysis liquid per 1000 gallons of de-ionized
water. Samples were sealed in high density polyethylene Nalgene bottles
and placed in a hot oil bath at 80° C. test temperature. Break
time is shown in Table 3 as visually determined. The results indicate
that break time is a function of aqueous phase pyrolysis liquid
concentration which provides a high degree of control.

[0161] In this description, reference has been made to multiple
embodiments and to the accompanying drawings in which are shown by way of
illustration specific exemplary embodiments of the invention. These
embodiments are described in sufficient detail to enable those skilled in
the art to practice the invention, and it is to be understood that
modifications to the various disclosed embodiments may be made by a
skilled artisan.

[0162] Where methods and steps described above indicate certain events
occurring in certain order, those of ordinary skill in the art will
recognize that the ordering of certain steps may be modified and that
such modifications are in accordance with the principles of the
invention. Additionally, certain steps may be performed concurrently in a
parallel process when possible, as well as performed sequentially.

[0163] All publications, Internet sites, patents, and patent applications
cited in this specification are herein incorporated by reference in their
entirety as if each publication, patent, or patent application were
specifically and individually put forth herein. Any Internet site
contents and publications available on the Internet are incorporated
herein as of the filing date of this patent application, even if such
Internet sites or publications later become unavailable.

[0164] The embodiments, variations, and figures described above provide an
indication of the utility and versatility of the present invention. Other
embodiments that do not provide all of the features and advantages set
forth herein may also be utilized, without departing from the spirit and
scope of the present invention. Such modifications and variations are
considered to be within the scope of the principles of the invention
defined by the claims.